Multispool control valve with limited series operation



Dec- 16, 19 9 D. OLDENBURG ET AL 3,483,890

MULTISPOOL CONTROL VALVE WITH LIMITED SERIES OPERATION Filed June 15, 1967 2 Sheets-Sheet 1 INVENTORS DORRANCE OLDE RG JAMES E. SCHEI DONALD L. SHOOK ATTORNEYS Dec. 16, 1969 QLDENBURG ET AL 3,483,890

MULTISPQOL CONTROL VALVE WITH LIMITED SERIES OPERATION Filed June 15, 1967 2 Sheets-$heet 2 INVENTORS DORRANCE OLDENBURG JAMES E. SCHEIDT DONALD L. SHOOK United States Patent US. Cl. 137-59612 4 Claims ABSTRACT OF THE DISCLOSURE A valve for controlling the operation of two double acting jacks having a first valve member with two positions for causing operation of one jack in two directions, and a second valve member for controlling the operation of the second jack in two directions, in which the passages between the valve members are so related that the second valve member is in series with the first, only when the first is in a certain one. of its two positions.

The valve of the present invention is designed for and will be described herein in association with the lift and tilt mechanism of a bucket loader. Its use for other purposes, however, is quite possible and will be understood as the description proceeds. The bucket of a conventional loader is carried by lift arms pivoted to and extending forwardly or rearwardly from a loader tractor. Tilt linkage. controls the attitude of the bucket on the lift arms, tilting it forwardly to a dump position, or tilting it rearwardly to a rack back position. Both lift and tilt operations are controlled by hydraulic jacks, and pressure to the jacks is usually controlled by valve spools in a common housing. Valves in series are, generally speaking, preferred for controls of this type, but there are some instances where series operation is a disadvantage. During the load cycle of the bucket, the power available is often insufiicient to completely load the bucket with a single forward crowding motion. Manipulation of the bucket is resorted to and a so-called fishtailing motion has been found very efiicient. This motion is best accomplished if lifting and dumping motions can be efiected at once, as with valves in series, but rack back and lifting cannot be accomplished at once. This will be more fully explained in the ensuing specification.

It is the object of the present invention to provide a valve capable of operation in the manner and for the purpose described above and having the beneficial results referred to, as well as others that will become evident as the description proceeds.

In the accompanying drawings:

FIGURE 1 is a view in side elevation of the forward portion of a tractor, showing a loader bucket and illustrating schematically the various motions utilized in loading the bucket by the method known as fishtailing; and

FIGURE 2 is a partially schematic section through a valve housing containing lift and tilt valve mechanisms embodying the present invention.

In FIGURE 1, the tractor generally indicated at carries a bucket 11 on a pair of forwardly extending lift arms, one of which is shown at 12. The lift arms can be raised and lowered about a pivot 13 by lift jacks, one of which is shown at 14. The attitude of the bucket 11 on the lift arms is controlled by conventional tilt linkage generally indicated at 15, and including tilt jacks, one of which is shown at 16. These jacks are operated to swing the bucket about its pivotal connection 17 with the lift arms through linkage, which is well-known. Raising and lowering the buckets with the lift jack 14 imparts swinging ice movement to the lift arms 12 in the direction of the arrow labeled lift. Actuation of the tilt linkage through the tilt jacks 16 causes forward and rearward swinging of the bucket about the pivot 17 in the direction of the arrow indicated as rack back-dump.

The power afforded by the tractor engine, which also supplies power for compressing hydraulic fluid for actuating the jacks is, under some circumstances, inadequate to crowd the bucket forwardly into a supply of material and fully load the bucket in a single motion. Operators have taken to manipulating the bucket in such a manner as to acquire a full load rapidly and efliciently with the power at hand. One of the most favored operations of this type is called fishtailing, and the sequential movements in this operation are indicated in FIGURE 1. In this figure, the bucket is shown in its load position wherein its bottom is approximately parallel to the ground, and the approach to the material to be loaded, generally indicated at 19, is made with the lift jacks 14 energized to raise the bucket 11. Raising or lifting while loading the bucket is also preferred because it transfers weight to the tractor, increasing traction when it is most needed. This crowding an liftting motion is continued through a distance represented as A-B in FIGURE 1, and terminates at about the point where it might be expected that the tractor and lift jacks would stall. At this point, the operator actuates the tilt jacks toward rack back to raise the cutting edge through the distance B-C. This is preferably accomplished without continued lifting movement to maintain the cutting edge as low as possible when it attains the point C. This discontinuing of the lift motion occurs automatically, as will presently be explained. At C, the operator swings the bucket toward its dump position, which will automatically be accompanied by a resumption of lifting, the combined actions causing a forward and slightly downward movement as shown as 0-D, and then a continued upward movement to the point B, at which time, as is apparent from FIGURE 1, racking back of the bucket will cause a probable shearing of material, as indicated by the broken line 20, with result that ample material has been undermined or embraced by the cutting edge to completely fill the bucket upon raising thereof with the lift jacks, which occurs automatically at the termination of the rack back stroke.

One of the advantages of the loading cycle, schematically shown in FIGURE 1, is that it relieves the operator of concern, as well as energy required for manipulating the lift valve during the entire operation. This is true because the lift valve is automatically taken out of control during rack back operation of the tilt cylinder. Consequently, from B to C, where lifting is not desired, the lift valve is disabled and again when the point E has been reached, racking the bucket back to its level position will disable the lift valve but, as soon as the bucket is level, the lift valve will take over automatically to raise the bucket to its carry position.

Referring now to FIGURE 2 of the drawings, a valve housing generally indicated at 24 is illustrated as containing a reciprocable control spool 25 for controlling the tilt cylinders represented at 16 and a similar spool 26 for controlling the lift cylinders represented at 14. Both spools are provided with centering spring assemblies shown at 27 and 28, respectively, and of well-known construction for holding the spools in a neutral or hold position. The tilt spool 25 is movable in opposite directions from the hold position between dump and rack back positions, as indicated at the left end of the spool where control linkage may be connected with it. The lift spool 26 is movable to opposite sides of its hold position to raise and lower positions and also to a float position, which may be disregarded for the purposes of understanding the present invention.

Fluid under pressure to actuate the lift and tilt cylinders is supplied from a pump represented at 30, which delivers fluid from a reservoir 31 through a filter 32 to a passage 33 in the housing 24. With both valves in hold position as shown, the fluid under pressure passes through the cylinder of the spool 25 on opposite sides of a land 35, which is provided with the usual metering slots shown at 36. This fluid continues downwardly into a passage 37 and flows through the cylinder of the spool 26 on opposite sides of a land 38. It is then communicated to an outlet passage 39 from which it is returned to the reservoir.

Since the spools of the valves, as described at this point, are arranged in series, the lift cylinder may be actuated with the tilt valve in its hold position; and as is apparent from FIGURE 2, with the lift valve shifted to its raise position, the land 38 thereon and a land 41 will close communication between passages 37 and discharge port 39. Now, pressure will open a check valve 42 biased toward its closed position by spring 43 and pass through a passage 44 and suitable metering slots 45 to a chamber 46. This chamber communicates with the head end of the lift cylinders 14 by a line represented at 48. Upon actuation of the lift cylinder, fluid will discharge from its rod end through a line 49 communicating with a chamber 50 which, in the raised position of the valve, communicates through metering slots 51 with a chamber 52, thence through passage 53 to passage 39 to be discharged.

As previously pointed out, it is desirable to actuate the bucket toward a dump position during the lift operation, but to preventlifting of the bucket while it is being actuated toward a rack back position. To dump the bucket, spool 25 is moved toward the right or dump position as indicated, blocking passage of fluid from chamber 33 through to spool 26 and causing pressure to open a second check valve 55. This admits fluid through passage 56 and slots 57 to chamber 58, from which pressure is com municated through a line 59 to the head end of the tilt cylinders. Discharge from the rod end of the tilt cylinders is directed through a line 60 to a chamber 62, thence through slots 63 to a passage 64, which communicates with check valve 42 so that the raising function of the lift cylinders is not interrupted. When the tilt cylinder spool is moved to its rack back position, communication is again closed between passages 33 and 37, and valve 55 is again opened and pressure is directed to the rod end of the cylinders through slots 63, chamber 62 and line 60.

In this case, since it is desired to discontinue the raising a function of the lift cylinders, return fluid from the head end of cylinders 16 fiows to chamber 58, thence through slots 57 to a chamber 62, which communicates by a passage indicated in dotted lines with chamber 52, and thence to passage 53 and discharge port 39. Thus, no pressure is available to open check valve 42 and actuate the lift cylinder.

What is claimed is:

1. Valve means suitable for actuating two sets of hydraulic motors as in the lift and tilt circuits of a bucket loader comprising first and second valves, said first valve being operable to control operation of a first set of motors in two directions, means operable when said first valve is positioned to operate said first set of motors in one direction and to direct fluid returned from said first set of motors to a second valve operable to control operation of a second set of motors for series operation, and means operable when said first valve is in position to operate said first set of motors in the opposite direction to bypass return fiuid around said second valve whereby the operability of said second set of motors is prevented.

2. The combination of claim 1 in which each valve comprises a valve spool connected in open center relationship in a pressure circuit with series flow from said first valve to said second va'lve when the first valve is actuated in one direction, and with a bypass to source when the first valve is actuated in the opposite direction.

3. The combination of claim 1 in which one valve is in lift circuit of a bucket loader and the other is in the tilt circuit and in which operation of the tilt circuit valve in one direction prevents operation of the lift circuit valve to raise the bucket.

4. The combination of claim 3 in which the tilt circuit valve is operable in two directions to cause rack back and dumping of the bucket, and in which operation of the bucket lift valve is ineffective while the tilt valve is in rack back position.

References Cited UNITED STATES PATENTS 2,247,140 6/1941 Twyman 91-4l4 3,000,397 9/1961 Schmiel 137-59613 3,008,488 11/1961 Vander Kaay et al. 9l414 XR 3,175,580 3/1965 Krehbiel 91-414 XR HENRY T. KLINKSIEK, Primary Examiner US. Cl. X.R. 914l4 Disclaimer 3,483,890.1)0rranee Oldenburg, Peoria, James E. Schez'dt, J oliet, and Donald L. Shook, East Peoria, Ill. MULTISPOOL CONTROL VALVE WITH LIMITED SERIES OPERATION. Patent dated Dec. 16, 1969. Disclaimer filed Aug. 20, 1970, by the assignee, (him-pillar Trac- Mr (10. Hereby enters this disclaimer to claims 1 and 2 of said patent.

[Ofiez'al Gazette December 8, 1.970.] 

